This invention relates to a method of spinning all-wool yarn on an improved cotton system, in which the all-wool yarn with the same quality of usual worsted yarn can be spun on the improved cotton system.
All-wool yarn must be spun on worsted system, or on woolen system, however, it has not been successfully spun, on cotton system. On a worsted system, procedures and devices therefor, are different from those of the cotton system. Wool staple length is long and distribution of the length usually is extremely uneven compared to those of cotton. Wool top is virtually impossible to draft with roller drafting, mechanism. Good uniformity of product requires faller bar incorporation into the process.
If a distance between drafting rollers could be set in accordance with the longest fiber length, shorter fibers would be floated, when being drafted, while longer fibers that exceed the distance between the rollers, would be broken or cut. In the former case, fallers must be applied on gill frame to control these floating fibers.
Recently, cotton-wool blended yarns are spun with squared wool fiber, but all-wool yarns like worsted yarns cannot be spun by means of the conventional cotton system until now. With worsted yarns produced by the conventional worsted yarn system, long fibers of more than 120 mm length of wool top occupies only about 10% of the total. Therefore, for the purpose of uniform drafting, gilling should be used. However, in general, worsted spinning system is considered as of higher cost and lower in productivity, which results in much higher spinning costs in worsted system than in cotton system.
In this connection, the purpose of the present invention is to provide spun-worsted-like wool yarns on improved cotton system with considerable lower cost, as well as higher productivity and good quality.
The present invention starts from two fundamental findings:
1. About 10% of longer fibers of wool top require extra-long distance of drafting rollers, that is, about 10% of wool fiber is abnormally long,
2. These abnormally long fibers can be cut on cotton drawing frame with suitable distance between two pairs of the drafting rollers. Staple length distribution of this cut wool top becomes shorter and becomes more uniform, enabling the cut top to be suitable for roller drafting without any fallers. This cut fleece of wool can proceed to later passages of drawing, roving, ring spinning on the conventional cotton system.
In the conventional prior art, Raboisson's drafting mechanism which is disclosed in U.S. Pat. No. 3,105,998, can be applied on roving frame and ring frame to draft wool fibers which are much longer than those of cotton.
However, Raboisson's drafting mechanism cannot work for all-wool yarn, because:
1. The distance between two pairs of rollers must always be wider than the longest fiber length. The majority of wool has the longest fiber longer than the maximum available distance between front and back rollers of drawing, roving and ring frame commercially running cotton system, so that it is substantially impossible for all wool to be processed with the Raboisson's mechanism on the line of the cotton system.
2. In case of wool comprised with comparatively shorter staple length, the variation of the staple length is too great, and the distance between the rollers is too wide to draft this wool. The floating fibers disturb good drafting. As a result, quite uneven sliver, roving and yarn are produced which are of no commercial value at all.